Field of the Invention
The invention relates to the field of sensing such as for example biosensing. More particularly, the present invention relates to methods and systems for multiplexed, i.e. simultaneous, sensing or characterizing samples in microfluidic devices, such as for example used in sequencing applications.
Technical Background
For a number of sensing applications, such as for example different biosensing applications, the need for multiplexed processing is high. In several applications, a large number of sensing events needs to be performed for obtaining an accurate characterization of a sample. One example of such an application whereby a large number of sensing events are required is sequencing. To obtain sufficiently efficient characterisation systems, there is a constant pressure from the market for increasing the number of sensing events that can be obtained with a microfluidic chip per day. In order to increase this number, the number of sensing sites can be increased. The density of sensing sites that can be introduced on a microfluidic chip can be high, e.g. more than 104, more than 105, more than 106, etc.
Alternatively, for increasing the number of sensing events that can be obtained, also the time required for performing the sensing and making the chip again ready for further sensing can be shortened. Especially in case a washing step is required for preparing the chip for further use, such as for example in the case of sequencing by synthesis, the time required for getting the different fluids at the proper position may be an important factor influencing the overall time required for a sensing event. Although a number of different techniques have already been suggested for improving the time required for a sensing event, e.g. in a sequencing application, further improvement is needed if high speed processing, e.g. at a rate of at least 100 Gbp/day or even better at a rate of at least 300 Gbp/day.
In addition to increasing the speed of sequencing devices there is also a need to reduce the overall cost. A washing step contributes to higher costs as large amounts of reagents are needed in the case of sequencing by synthesis.